Reaction #1135825

Reaction equation

product

3-(4-hydroxyphenyl)-4-(4-methoxyphenyl)-2H-chromen-7-ol

ethanol

→

3-(4-hydroxyphenyl)-4-(4-methoxyphenyl)-8-methyl-3,4-dihydro-2H-chromen-7-ol

Conditions

Workup

1. 1
   Otherfor 3 hours
2. 2
   FiltrationThe reaction was filtered through Celite
3. 3
   Otherto remove the catalyst
4. 4
   Washrinsed through with ethanol (100 ml)
5. 5
   ConcentrationThe filtrate was concentrated to ˜15 ml
6. 6
   workup.ADDITIONbefore being poured
7. 7
   Temperatureinto chilled
8. 8
   OtherA pale orange precipitate formed which
9. 9
   Otherthen formed a brown oil
10. 10
    ExtractionThe mixture was then extracted with diethyl ether
11. 11
    Washthe combined organic layers washed with water (3×100 ml), brine (1×100 ml)
12. 12
    Dryingdried over anhydrous magnesium sulphate
13. 13
    Filtrationfiltered
14. 14
    OtherThe solvent was removed in vacuo
15. 15
    Otherto give red/brown oil
16. 16
    OtherThe product was recrystallised from diethyl ether (˜15 ml)
17. 17
    Otherto give brown solid which
18. 18
    Washwas rinsed with chilled diethyl ether
19. 19
    Otherto give off-white crystals

Procedure

2.5 g of the product of step 8, 10% Pd/Al2O3 0.4 g and 50 ml of ethanol were combined in a 2-neck 100 ml round bottom flask. The reaction was hydrogenated at low pressure using standard conditions for 3 hours. The reaction was filtered through Celite to remove the catalyst, rinsed through with ethanol (100 ml). The filtrate was concentrated to ˜15 ml before being poured into chilled, stirred water (300 mL). A pale orange precipitate formed which then formed a brown oil. The mixture was then extracted with diethyl ether, the combined organic layers washed with water (3×100 ml), brine (1×100 ml), dried over anhydrous magnesium sulphate and filtered. The solvent was removed in vacuo to give red/brown oil. The product was recrystallised from diethyl ether (˜15 ml), to give brown solid which was rinsed with chilled diethyl ether to give off-white crystals. 4 crops of (IV), ˜1 g. The 1H NMR spectrum and numbering scheme being shown below.

Source